Expansible subsurface well bore apparatus



Dec, 21, 1965 B. J. CORDARY ETAL 3,224,507

EXPANSIBLE SUBSURFACE WELL BORE APPARATUS 2 Sheets-Sheet 1 Filed Sept. 7, 1962 Li 14L United States Patent 3,224,507 EXPANSIBLE SUBSURFACE WELL BORE APPARATUS Bruce J. Cor-dairy, Los Alamitos, and Charles 0. Van Note,

Jr.,- Rolling Hills, Calif., assignors to The Servco Company, Long Beach, Calif., a corporation of Nevada Filed Sept. 7, 1962, Ser. No. 222,051 6 Claims. (Cl. 166-553) This invention relates to a subsurface well bore apparatus.

In operations in subsurface well bores, as, for example, those conducted in connection with drilling of oil wells, apparatus are frequently utilized in which working members or arms occupy a retracted position while the apparatus is lowered through the well bore and are subsequently expanded radially outwardly for use at a selected depth. Such a structure enables free passage down the well bore and operative expansion of the arms at the selected depth. Examples of such apparatus include devices known as milling cutters and hole enlarging devices. In the type of milling cutter commonly called a section mill, for example, the arms of the mill are expanded outwardly at the selected depth both to cut through a tubular conduit or casing in the well bore, and to mill a section of the casing to form an open section or window. Similarly, in hole enlarging devices, the arms of the apparatus occupy a retracted position as the apparatus is lowered through the well bore or casing, and are then expanded radially outwardly at the selected depth to enlarge the well bore by cutting action.

in the use of tools having expansible arms, as described, it is desirable to provide to the surface some indication by which it can be ascertained that the expansible arms have attained an expanded position. Otherwise, if a malfunction of the apparatus or an unexpected obstruction within the well bore prevents expansion of the arms, considerable time may be expended in operation of the tool without fulfillment of its intended function.

The present invention is a subsurface well bore apparatus that provides a clear indication to the surface whenever the expansible arms have reached an expanded position. The present invention comprises a tubular body which is adapted to be secured to a drill string and has a passage. A plurality of expansible arms are secured to the tubular body for movement of the arms radially outwardly from the body. Within the passage, a slidable means is provided which is movable responsive to changes in pressure of a fluid flowing through the passage. Movement of the slidable means causes it to engage the plurality of expansible arms to produce radially outward movement of the arms. Within the passage, an orifice is provided and a constricting means is disposed relative to the orifice to restrict flow of fluid through the orifice. The orifice and the constricting means are constructed so that movement of one relative to the other varies flow of fluid through the orifice. Means are provided for moving the orifice and the constricting means relative to each other responsive to movement of the slidable means.

In one embodiment according to the present invention, the orifice is formed within a slidable means that is movable responsive to applied fluid pressure. The constricting means, while disposed relative to the orifice to restrict flow through the orifice, is fixed in position. Movement of the slidable means including the orifice upon application of fluid pressure changes the position of the constricting means relative to the orifice and thereby changes the orifice area through which fluid is flowing. The change in orifice area is arranged -to occur when the slidable means engages the expansible arms to produce radially outward movement of the arms into an operative 3,224,507 Patented Dec. 21, 1965 position. The change in orifice area results in a change in back pressure of the fluid, which is indicated by appropriate means at the surface and signifies that an expanded position of the expansible arms has been attained.

While the present invention is applicable to a variety of subsurface well bore tools, it is particularly described herein with reference to the milling cutter known as a section mill. From such a description, the applicability of the present invention to other subsurface tools will be readily apparent to those skilled in the art.

The structure of the apparatus according to the present invention together with its advantages and method of operation will become more apparent from the following detailed description made in conjunction with the accompanying drawings in which:

FIG. 1 and FIG. 1A are an elevational view, partially sectioned, of the upper and lower portions, respectively, these being set out side by side, of an embodiment of a milling cutter according to the present invention, and show the cutter in a retracted position; and

FIG. 2 and FIG. 2A are an elevational view, partially sectioned, of the upper and lower portions of the embodiment of FIG. 1 and FIG. 1A and show the embodiment in an expanded position.

In the embodiment of the invention shown in FIG. 1 and FIG. 1A, the milling cutter is in a retracted position for passage down a tubular conduit or casing. A top sub 10 includes an upper tool joint 12 which can be threadably engaged to drill pipe forming the drill string by which the milling cutter is lowered into the well bore. The top sub also includes a lower tool joint 14 threadably engaged to a tubular body 16 of the apparatus according to the present invention. A central passage 18 extends longitudinally through the top sub for flow of fluid.

The tubular body has a continuous central passage formed by an upper passage 20, an intermediate passage 22, and a lower passage 24. The diameter of the intermediate passage is smaller than the diameter of either upper and intermediate passages and a shoulder 28, as being formed in the tubular body at the juncture of the upper and intermediate passage and a shoulder 28, as seen in FIG. 1A, being formed in the tubular body at the juncture of the lower and intermediate passages.

A flow control assembly is positioned in the upper portion of upper passage 20, as particularly seen in FIG. 1. The flow control assembly includes a body 32 pe ripherally joined as by welding to the inner wall defining passage 20 in tubular body 16. While the body of the flow control assembly may be formed in other ways, the body of the embodiment in FIG. 1 is formed from an upper cone element 34 extending upwardly into passage 18 of the top sub and a lower element 35. A recess 36 in the cone element mates with a bore 37 of reduced diameter in lower element to form a shoulder 38 when the two body elements are joined. A stinger 39 includes a head 40 having a diameter substantially equal to the diameter of the recess and a cylindrical rod 41 of reduced diameter extending downwardly from the head. The head of the stinger is supported on shoulder 38 within body 32. A cushioning coil spring 42 is disposed between the head of the stinger and a stopper 44 which abuts the top inner surface of recess 36. A plurality of flow passages 46, formed by mating passages in the cone and lower elements, extend through the body 32 to provide flow communication between the portions of passage 20 above and below the body of the flow control assembly.

A piston assembly 48 disposed in the passage of the tubular body, as is hereinafter described, includes a piston head 50 and a piston stem 52. The piston head includes an upper piston packing 54 secured to the head by a ring 56 and retaining screws 58. A lower piston packing 59 is positioned in a peripheral recess 60 of the piston head. The piston stem has a diameter such that it is slidably movable within the intermediate passage of reduced diameter in tubular body 16 and is joined at its upper end within the upper passage to the piston head. The lower end of the piston stem extends, as is shown in FIG. 1A, into lower passage 24 of the tubular body. A compression spring 61 is placed around the portion of piston stem 52 in upper passage 20 so that the spring is compressibly positioned between the lower surface of piston head 50 and shoulder 26 formed in the tubular body.

As shown in FIG. 1A, a cam 62 is threadably fitted to the lower end of the piston stem and is retained in place by a cam lock nut 64. The diameter of the cam is substantially equal to the diameter of lower passage 24 so that it is slidably movable therein. The piston assembly has a central bore 66 extending through its length.

At the upper end of the piston assembly, bore 66 is enlarged to accommodate an orifice assembly 68. The orifice assembly includes a sleeve 70 and an orifice-forming member 72 defining a central orifice passage 73. The lower portion of the orifice passage has a diameter substantially equal to the diameter of bore 66 extending downwardly from the orifice assembly within the piston assembly. The diameter of the upper portion of the orifice passage gradually increases in the direction of the top of the piston assembly by reason of an outward divergence of the orifice-forming member at its upper end. O-rings 74 provide a seal between sleeve 72 and the piston assembly, and O-rings 76 provide a seal between orifice-forming member 72 and the sleeve.

The diameter of the lower portion of the orifice passage is slightly larger than the diameter of cylindrical rod 41 of stinger 39 of the flow control assembly so that the annular area between rod 41 and the orifice-forming member provides an orifice area for flow of fluids when the cylindrical rod extends into the lower portion of the orifice passage. The upper diverging portion of the orifice-forming member provides a larger annular area between the cylindrical rod of the stinger and the orifice forming member. As shown in FIG. 1A, a plurality of cutter arms, of which two are shown and identified by reference character 78, are supported at their upper end for pivotal movement on .hinge pins 80 retained in tubular body 16 by pin retaining screws 84. A lug 82 is inset in a recess 86 in the outer surface of tubular body 16 and is retained therein by a screw 88 so that each lug is substantially flush with the outer surface of the tubular body. The lug provides a bearing surface for the upper end of the cutter arm to absorb shock and thrust. The portion of each cutter arm depending from the hinge pin is accommodated within a longitudinal slot 90 in the tubular body. A cutter blade 92 extends outwardly from the outer edge of each arm and includes a cutting edge 94 and a cutting tip 96. The inner edge of each arm is shaped to provide a cam surface 98, and the lower end of each arm is notched to form an integral tab 100.

Each cutter arm is fitted within its longitudinal slot so that, while movable, only a small amount of fluid leakage between lower passage 24 and the outside of the tubular body occurs even in the absence of any packing. An arm stop 102 is mounted in a recess 104 in the outer surface of the tubular body and is positioned to engage tab 100 of each arm to limit the radially outward movement of the cutter arm. The arm stop is secured to the tubular body by screws 106.

The milling cutter according to the present invention is shown in FIG. 1 and FIG. 1A in the position in which spring 61 biases the piston assembly so that the upper surface of cam 62 abuts shoulder 28 of the tubular body. Cam 62 is not in engagement with cam surfaces 98 of the cutter arms and the cutter arms are in a retracted positionwith the cutter blades being substantially within the outer circumference of the tubular body. In this position of the piston assembly, the length of cylindrical rod 41 of the stinger is such that it extends within the orifice passage into its lower portion of reduced diameter.

As the milling cutter is lowered through the casing, no fluid pressure is applied and the elements of the cutter remain in the position shown in FIG. 1 and FIG. 1A. When the selected depth is reached, fluid pressure is applied by surface pumps to pump a fluid, such as gas, water or drilling mud, through the drill string and into passage 18 of the top sub. The pumped fluid then passes through openings 46 of the flow control assembly, the lower portion of passage 20, and through the orifice area in the orifice passage as defined by cylindrical rod 41 of stinger 39. The fluid passing through the orifice area then suc cessively flows through bore 66 of the piston assembly, lower chamber 24 of the tubular body, and leaves the milling cutter through its open bottom end. The orifice area between the cylindrical rod and the orifice passage produces a flow restriction which results in a pressure differential between the top and bottom ends of piston assembly 48. This pressure differential produces a downward movement of the piston assembly, as will hereinafter be described in greater detail.

FIG. 2 and FIG. 2A show the embodiment of the milling cutter of FIG. 1 in the position where the cutter arms have reached a fully expanded position. The elements of the apparatus shown in FIG. 2 and FIG. 2A are identical to those which have been described with reference to FIG. 1 and FIG. 1A, and the same reference characters are used to designate these elements.

Pumping of fluid from the surface, as previously described, produces a pressure differential which moves piston assembly 48 downwardly against resistance of spring 61. The downward movement of the piston assembly causes cam 62 to engage cam surfaces 98 of the cutter arms whereby the cutter arms are moved radially outwardly from the tool body to engage the casing for cutting and milling. In the position of the arms shown in FIG. 2A, the arms are fully expanded and have cut through the casing. Rotation of the drilling tool results in milling of the casing. In the position shown in FIG. 2A, the cutter arms have been expanded the maximum radially outward distance and have engaged stops 102 which limit further outward movement.

The downward movement of the piston assembly including the orifice assembly causes the stationary cylindrical rod of stinger 39 to be withdrawn from the lower portion of the orifice passage. The end of the cylindrical rod reaches a position within the portion of the orifice passage having an enlarged diameter, as shown in FIG. 2. The orifice area defined by the annular area in the new position of the cylindrical rod within the orifice-forming member isjenlarged so that a larger volume of fluid passes through the orifice area. A decrease of fluid back pressure thereby occurs.

The length of the portion of the orifice passage of reduced diameter relative to the length of the cylindrical rod is such that the lower end of the cylindrical rod is within the portion of increased diameter of the orifice passage at the time when the cutter arms have reached the fully expanded position shown in FIG. 2A. The reduction in back pressure resulting from the change in position of cylindrical rod 41 within the orifice passage from the position shown in FIG. 1 tothe one shown in FIG. 2 is registered at the surface and thereby signals that the arms have reached a fully expanded position.

An advantage particularly applicable to milling cutters is accrued in that a larger volume of fluid is obtained for removal of cuttings at the time when milling of the casing is commenced. While cutting of the casing in a lateral direction is underway, a higher pressure differential across the piston assembly results together with a smaller volume of fluid flow through the orifice area. When the lateral cutting of the casing has been completed and downward milling is commenced, a larger fluid volume flows through the orifice area and a significant decrease in back pressure is obtained.

A further feature of the embodiment according to the invention shown in the drawings lies in the use of a flat 106 on each of the cutter arms. The length of the flat is correlated to the length of the orifice passage of enlarged diameter so that whenever an oscillation in pump pressure causes cam 62 to be disengaged from the fiat, as when the cam is raised into engagement with cam surface 98, the flow assembly is in a full choke position. In this position, cylindrical rod 41 of the stinger is within the lower portion of the orifice passage and a high pressure differential is obtained. This feature is advantageous since a corrective response to oscillation in pump pressure is obtained by which the arms are maintained in a fully expanded milling position.

Various modifications may be made Within the scope of the invention as herein described. As one example, a separate orifice area may be provided relative to which an inverted stinger including a cylindrical rod is made movable by attachment to the piston assembly. This and other modifications by which the relative movement of the orifice assembly with respect to a constricting means is achieved become apparent in the light of the invention herein disclosed.

We claim:

1. A subsurface well bore apparatus comprising:

(a) a tubular body adapted to be secured to a drill string and having a central passage;

(b) a plurality of expansible arms secured to the tubular body and adapted to occupy a retracted position and an expanded position;

(c) slidable means movable within the passage responsive to changes in pressure of a fluid passing through the passage to engage the plurality of expansible arms to place them in an expanded position;

(d) orifice-forming means within the passage and defining orifice passages having a first diameter and a second larger diameter;

(e) constricting means extending into the orifice pas sages to provide a first orifice area adjacent the orifice passage having the first diameter and a second larger orifice area adjacent the orifice passage having the second diameter; and

(f) the slidable means including means whereby movement of the slidable means moves the orifice-forming means and the constricting means relative to each other to provide only the second orifice area when the expansible arms are in the expanded position.

2. A subsurface well bore apparatus comprising:

(a) a tubular body adapted to be secured to a drill string and having a central passage;

(b) a plurality of expansible arms secured to the tubular body and adapted to occupy a retracted position and an expanded position;

(c) slidable means movable within the passage responsive to changes in pressure of a fluid passing through the passage to engage the plurality of expansible arms to place them in an expanded position;

(d) orifice-forming means within the passage and defining orifice passages having a first diameter and a second larger diameter;

(e) a cylindrical rod depending into the orifice passages to provide a first orifice area adjacent the orifice passage having the first diameter and a second larger orifice area adjacent the orifice passage having the second diameter; and

(f) the slidable means including means whereby movement of the slidable means moves the orifice-forming means and the constricting means relative to each other to provide only the second orifice area when the expansible arms are in the expanded position.

3. A subsurface well bore apparatus comprising:

(a) a tubular body adapted to be secured to a drill string and having a central passage;

(b) a plurality of expansible arms secured to the tubular body and adapted to occupy a retracted position and an expanded position;

(c) slidable means movable within the passage responsive to changes in pressure of a fluid passing through the passage to engage the plurality of expansible arms to place them in an expanded position;

(d) the slidable means having a bore extending therethrough;

(c) orifice-forming means within the bore and defining orifice passages having a first diameter and a second larger diameter; and

(f) a stationary cylindrical rod depending into the orice passages to provide a first orifice area adjacent the orifice passage having the first diameter and a second orifice area adjacent the orifice passage having the second diameter;

(g) the cylindrical rod having a length such that the first orifice area is provided when the expansible arms are in the retracted position and only the second orifice area is provided when the expansible arms are in the expanded position.

4. An apparatus for cutting and milling a tubular conduit disposed in a well bore comprising:

(a) a tubular body adapted to be secured to a drill string and having a central passage;

(b) a plurality of expansible cutter arms secured to the tubular body and adapted to occupy a retracted position and an expanded position;

(c) a piston reciprocably movable within the passage responsive to changes in pressure of a fluid passing through the passage to engage the plurality of cutter arms to place them in an expanded position;

(d) orifice-forming means within the passage and defining orifice pas-sages having a first diameter and a second large diameter;

(e) constricting means extending into the orifice passages to provide a first orifice area adjacent the orifice passage having the first diameter and a second larger orifice area adjacent the orifice passage having the second diameter; and

(f) the piston including means whereby movement of the piston moves the orifice-forming means and the constricting means relative to each other to provide only the second orifice area when the cutter arms are in the expanded position.

5. An apparatus for cutting and milling a tubular conduit disposed in a Well bore comprising:

(a) a tubular body adapted to be secured in a vertical position to a drill string and having a central passage;

(b) a piston reciprocably movable within the central passage;

(0) a plurality of depending cutter arms, each secured at one end to the tubular body for pivotal movement of the other end of the arm from a retracted position to an expanded position and disposed in slots in the tubular body so that a portion of each arm extends inwardly into the passage, each arm having (i) means at its other end for cutting and milling tubular conduits,

(ii) a cam surface on the portion of the arm extending inwardly into the passage to be operatively engaged by the piston;

(d) the piston having a bore extending therethrough;

(e) orifice-forming means within the bore and defining orifice passages having a first diameter and a second larger diameter;

(f) a stationary cylindrical rod depending into the orifice passages to provide a first orifice area adjacent the orifice passage having the first diameter and a second orifice area adjacent the orifice passage having the second diameter;

(g) the cylindrical rod having a length such that the firs-t orifice area is provided when the cutter arms are in the retracted position .and only the second orifice area is provided when the cutter arms are in the expanded position.

6. A subsurface Well bore apparatus comprising:

(a) a tubular body adapted to be secured to a drill string and having a central passage;

(b) a plurality of expansible arms secured to the tubular body and adapted to occupy a retracted position and an expanded position;

(c) slidable means movable Within the passage responsive to changes in pressure of a fluid passing through the passage to engage the plurality of expansible arms to move them to an expanded position;

(d) orifice-forming means within the passage;

(e) constricting means disposed relative to the orificeforming means;

(f) the orifice-forming means and the constricting means being shaped to provide a first orifice area and a second larger orifice area when the expansible arms are in a retracted position; and

8 (g) the slidable means including means whereby movement of the slidable means moves the orifice-forming means and the constricting means relative to each other to provide only the second larger orifice area when the expansible arms are in the expanded position.

References Cited by the Examiner UNITED STATES PATENTS 2,246,711 6/1941 Barrett et a1. 166-55.8 2,599,069 6/1952 Robishaw 166-55.8 2,602,642 7/1952 Baker 175269 2,699,921 1/1955 Garrison 175267 2,859,953 11/1958 Chadderdon 16655.'8 2,863,641 12/1958 Kammerer 16655.8 2,976,927 3/1961 Kammerer 16655.8 3,073,389 1/1963 Conner 166-55.8

20 CHARLES E. OCONNELL, Primary Examiner.

BENJAMIN HERSH, Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,224,507 December 21, 1965 Bruce J. Cordary et a1.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2, line 40, after "upper" insert passage 20 or lower passage 24, a shoulder 26 being formed in the tubular bod at the juncture of the upper lines 41 and 42, strike out "being formed in the tubular body at the juncture of the upper and intermediate passage and a shoulder 28, as"; line 70, for "passage" read passages Signed and sealed this 25th day of October 1966.

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Attesting Offioer Commissioner of Patents 

6. A SUBSURFACE WELL BORE APPARATUS COMPRISING: (A) A TUBULAR BODY ADAPTED TO BE SECURED TO A DRILL STRING AND HAVING A CENTRAL PASSAGE; (B) A PLURALITY OF EXPANSIBLE ARMS SECURED TOP THE TUBULAR BODY AND ADAPTED TO OCCUPY A RETRACTED POSITION AND AN EXPANDED POSITION; (C) SLIDABLE MEANS MOVABLE WITHIN THE PASSAGE RESPONSIVE TO CHANGES IN PRESSURE OF A FLUID PASSING THROUGH THE PASSAGE TO ENGAGE THE PLURALITY OF EXPANSIBLE ARMS TO MOVE THEM TO AN EXPANDED POSITION; (D) ORIFICE-FORMING MEANS WITHIN THE PASSAGE; (E) CONSTRICTING MEANS DISPOSED RELATIVE TO THE ORIFICEFORMING MEANS; (F) THE ORIFICE-FORMING MEANS AND THE CONSTRICTING MEANS BEING SHAPED TO PROVIDE A FIRST ORIFICE AREA AND A SECOND LARGER ORIFICE AREA WHEN THE EXPANSIBLE ARMS ARE IN A RETRACTED POSITION; AND (G) THE SLIDABLE MEANS INCLUDING MEANS WHEREBY MOVEMENT OF THE SLIDABLE MEANS MOVES THE ORIFICE-FORMING MEANS AND THE CONSTRICTING MEANS RELATIVE TO EACH OTHER TO PROVIDE ONLY THE SECOND LARGER ORIFICE AREA 